* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; overflow: hidden; background: #f0f0f0; }

.hidden { display: none !important; }

#auth-screen {
  display: flex; align-items: center; justify-content: center;
  height: 100vh; background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}
.auth-box {
  background: white; padding: 2rem; border-radius: 12px; box-shadow: 0 10px 40px rgba(0,0,0,0.2);
  width: 320px;
}
.auth-box h1 { text-align: center; margin-bottom: 1.5rem; color: #333; }
#auth-tabs { display: flex; margin-bottom: 1rem; }
.auth-tab {
  flex: 1; padding: 0.5rem; border: none; background: #eee; cursor: pointer;
  font-size: 0.9rem; transition: background 0.2s;
}
.auth-tab:first-child { border-radius: 6px 0 0 6px; }
.auth-tab:last-child { border-radius: 0 6px 6px 0; }
.auth-tab.active { background: #667eea; color: white; }
#auth-form input {
  width: 100%; padding: 0.75rem; margin-bottom: 0.75rem; border: 1px solid #ddd;
  border-radius: 6px; font-size: 0.95rem;
}
#auth-form input:focus { outline: none; border-color: #667eea; }
#auth-submit {
  width: 100%; padding: 0.75rem; background: #667eea; color: white; border: none;
  border-radius: 6px; font-size: 1rem; cursor: pointer;
}
#auth-submit:hover { background: #5a6fd6; }
#auth-error { color: #e74c3c; font-size: 0.85rem; margin-bottom: 0.5rem; }

#toolbar {
  display: flex; align-items: center; gap: 0.5rem; padding: 0.5rem 1rem;
  background: #fff; border-bottom: 1px solid #ddd; position: relative; z-index: 10;
  flex-wrap: wrap;
}
.toolbar-group { display: flex; align-items: center; gap: 0.25rem; }
.toolbar-group + .toolbar-group { border-left: 1px solid #ddd; padding-left: 0.75rem; }
.tool-btn {
  width: 36px; height: 36px; border: 1px solid #ddd; background: #fff;
  border-radius: 6px; cursor: pointer; display: flex; align-items: center;
  justify-content: center; font-size: 1.1rem; transition: all 0.15s;
}
.tool-btn:hover { background: #f5f5f5; }
.tool-btn.active { background: #667eea; color: white; border-color: #667eea; }
#style-group label { display: flex; align-items: center; gap: 0.3rem; font-size: 0.8rem; color: #666; }
#color-picker { width: 30px; height: 30px; border: none; cursor: pointer; padding: 0; }
#thickness-slider { width: 80px; cursor: pointer; }
#user-indicator {
  font-size: 0.8rem; color: #666; padding: 0.25rem 0.5rem;
  background: #f5f5f5; border-radius: 4px;
}
#logout-btn {
  padding: 0.35rem 0.75rem; background: #e74c3c; color: white; border: none;
  border-radius: 4px; cursor: pointer; font-size: 0.8rem;
}
#board-container { width: 100vw; height: calc(100vh - 49px); position: relative; }